Several techniques have been developed throughout the history of orthopedics and neurology as forms of intercession which would be efficient for the handicapped individual.
The most common technique employed was the manufacturing of thickened cables generally made out of wood, rubber, foam and plastic materials, fastened with a strip of leather, fabric or Velcro which are placed on, as example cutlery, pencils, wax chalk and razors. However such a adaptation is an impediment to the release of the feeble grasp or the associated reactions modifying the tonus of the muscles which is specially common in groups of patients such as they having cerebral palsy, AVC sequel, skull trauma sequel etc. Besides, quite often these devices are attached to the injured hands and in these cases it is impossible to avoid an unnatural and uncomfortable positioning of the hands.
Velcro and leather bandages are also used. In addition, splints made from heat molded materials which require a lot of handling in order to manufacture the orthesis, have also been previously used. These thermoplastic devices cover completely the palm and the back of the hand which can produce a rather unaesthetic effect and quite often produce chafing and scars in the abradable regions of the hand and obstruct the use of the sense of touch and cognitive recollection. Further they may cause swellings and discomfort due to sweating.
Seriously handicapped individuals as those with cerebral palsy spastics, dystonics, choreics, athetoids, spinal tetraplegics, patients with muscular dystrophy, demyelination, malformed, serious burns, rheumatoid arthritis, Parkinson's disease, etc., are totally incapacitated in the use of their hands, especially when exhibiting motor uncontrollability of the entire upper limb.
The most common technique to manufacture these types of devices requires appropriate measurements of the affected limb, development of drawings on paper, development of plaster cast of the compromised limb which can be quite painful some times, improvements on casting the plaster, removing the cast, fabricating the splint of aluminum, leather, neoprene or similar, providing the device with catches, washers, strings, or Velcro and, after this, carrying out many tests with the device. Usually, there is a need for several steps and the use of many elements to obtain a final product which has a rigid structure being specific for each individual. As these devices are produced during a specific pathological moment, any changes in the clinical status as well as any ergonomic alteration, as to weight (loss or gain), or as to size (in case of children and adolescents), shall make the orthesis incompatible with the new sizes thereby requiring the manufacture of a new orthesis.
Another plastic deformation technique can be used to produce some models for specific pathologies providing with the scaling of measurements to adapt themselves to the normal parametrs of a specific population group. However this technique will not allow for any ergonomic or anatomic adjustment. Also this technique causes a great deal of discomfort since this is not endowed with any system of ventilation and usually covers large areas of the affected limb or articulation.
An improved technology is the low temperature thermo-molding of plastic sheets which requires extremely accurate measurements and manufacturing of a paper mold, cutting, heating and application of the still hot product on the affected limb. After this the device is cured and finished by grinding the edges, installing the structural supports and the Velcro. In some cases it will be necessary to apply inside the vest, collar or splint a protective film or cushioning layer in view of the hardness of the material and also to avoid problems on the skin and with ergonomic development of the individual. As the first mentioned technique is specific for each case and for each different individual and given the nature of the thermo-molding material, it undergoes changes within approximately eight month and it will become brittle.
Another technology is disclosed in U.S. Pat. No. 4,617,921 and refers to an immobilizing structure consisting of a flexible compartment which contains internally a set of rods (called die material) and a thermoplastic product which envelopes the aforementioned rods and imparts shape to the structure depending of its physical state (whether solid or liquid), that is, depending on its temperature. As this device has a complex structure, a rigorous control is required for heating by both the manufacturer and the therapist who must be thoroughly trained in this technology in order not to cause any burns to the limb under treatment. In order to avoid the usual ordinary oscillations of temperatures in the work place, or even during a shower, the internal rods and its shapes (braided, twisted, etc.) must be carefully chosen. The thermoplastic material must be able to resist the repeated heating and cooling cycles and it must have an excellent thermal conductivity whereas the external compartment must be expansion proof. To produce this device, heating and cooling sources are needed. Therefore it requires an accurate monitoring of the temperature of said structure in order to guarantee the patient's safety.
Therefore, there is no means, until now, useful as an adapter or special device for the upper limbs that provides for any kind of independence without the help of a third party in order to be able to scribble or to paint on a sheet of paper, to write, to point a finger to a figure or an object, and/or to grasp anything.